Process for carrying out endothermic gas reactions



July 28, 1925.

1,547,714 H. NDRIESSENS Y PROCESS FOR CARRYING CUT ENDCTHERMIC GAS REACTIONS Patented 28,1 V

' To all whom it concern.:

v-UNITED STATES* `PATENI OFFICE.

IIUGo ANDnIEssENs, or zumos, SWITZERLAND, AssIGNoaror oNE-IIALF To THE l FIRM: socIETYroF CHEMICAL INDUSTRY IN nAsLE, or BASEL, SWITZERLAND.'

f rnocnss Iron cAnmr'rNG oU'T ENnbTIIEnMIc GAS IuincTIoN-s.-

' A;Spnmio nien retruary 1s, 1922. serial-No. 537,012.

Be it known that ILHU/o ANDRInssENs, a subject of the Queenof Netherlands, and resident of Zurich, Switzerland, have invented a new Process for Carrying Out Endothermic Gas Reactions, of which the following is a full, clear, and vexact specification.

It is known, that gasreactions carried out with ythe aid of the electric arc\ or other heating elements' give yields, which are the greater the steeper is the temperature fall of the gases'leaving the heating zone. l For this reason it is ladvantageous to lead the gas to bring to reaction with a speed as great as possible through the heating zone. But in the practice this was heretofore only feasible until a certain de ee, since the speed of the current diminis es the concen- 'be carried out in intervals, that is' to say, the described clrculation of a determined.

tration, that is to say, in other words, for

.the reason that, although per unity of energy and of time, more reaction product is obtained, this product is so diluted in the large quantity of gas led through the lfurnace,

thatits subsequent absorption meets with too great diiculties.

.The object ofthe present invention i s a4 process permitting to move the reaction gases with any desirable speedthrough the heating-zone and' to utilize consequently the strong temperature fallA resulting therefrom, withoutgthat on thev other hand an excessive dilution of the reaction product takes place.

The new process consists in the following:

Instead to conduct the gases to bring to reaction, after they have passed once through the heating element,y immediately to the absorption, thewhole gas mass is brought to circulate continuously and quickly, several times, through ythe heating element and cooled down each time after they leave lthe heating element. VThus isproduced on the other hand, behind the heating element a .very lstrong temperaturelfall and on the otherv hand the whole'circulating quantity of gas is by its repeated passages through the heating element, successively enriched so intensely with reaction product that there results'a mixture which seemsnomore excessivelydiluted and does consequently not oppose any diiiiculty to the absorption.

The accompanying vdrawing shows a scheme'of a plant ,capable of being employedv for carrying out the invention.

` va is a pipe through which the gas to bring to reaction is pressed b a blower b in a closed system of gascircu atingpipes 0. I n this system of ipes c is inserted a4 heatin element d as` on instance an electric arc evice and an accordingly greater blower e. A

part of the system of pipes c passes itself through a cooling device f. vAv pipe g serves to 4lead the gases finally to an absorption plant h. By the blower e the whole gasmass contained in the closed system of'pipes 0 receives a quick movement and lcirculates continuously through ,the same, they gas passes throughthe electric arc, then through the cooled part of the system of pipes o,

afterwards through the blower e, again through the electric arc and so forth until the desired enrichment of the gas-with reaction product is attained. i

In the practice the described process can quantity of gas through the system of pipes can be conducted to end and afterwards the same be led to the absorption plant and the circulation of a new quantity of gas through-,the system of pipes be brought about and so forth. But the gas circulation can also be a continuous one,vin such a manner that during the said circulation continuously new gas is introduced in the system of pipes c vand let -to diffuse into the whirling gas mass contained therein, whilst on the other hand continuously a quantity of gas corresponding to the quantity of new gas introduced in the circulating cycle is led out and conducted in the absorption plant.'

- By the employment of speeds of any height v for the gas current it becomes possible to introduce in the circulating cycle notv only gases but also solid substances,'for the purpose either of increasing the temperature gas mixture is caused to circulate quickly through the pi e system c, so that it passesA at d through t e elect-ric arc with a speed of about 20 to 25 meters per second. Under the intiuence of the electric arc due to the highv temperature prevailing therein, there is formed nitrogen oxide according to the formula N,-|O,=2NO, in rapidly increasing quantities by the continuous circulatlon of the reaction gases through the arc. In order to replace the quantities of nitrogen and of oxygen consumed by the formatlon of NO, some fresh mixture of nitrogen and oxygen is ncontinuously introduced in the pipe system c by means of the blower b. A corresponding gas volume 1s led out of the pipe system 0 through the outlet g andv is freed from NO2 in the absorption plant It, after it has been previously .passed through the oxidizing room, in whlch the NO combined with the excess oxygen to NO2. l The gases not absorbed in 7L are advantageously returned to the inlet a and conducted again therefrom mixed with fresh nitrogen and fresh oxygen, in the lpipe system c. Obviously it would be possible to insert in the pipe system c, instead of onlv one electric arc device d, several of suci electric arc devices, for example three, each connected to two of the three conductors supplying the heating device with a triphasic alternating current, whereby. a supplementary cooling device would be 1nserted between each couple of successive electric arcs.

What I claim is:

1. In a process for carrying out endothermic gas reactions wherein the gases are maintained in continual circulation through a heating device and a subsequent cooling path, the steps which consist in circulating the gases at a 'speed so high that under the infiuence of the excess of noncombined gases the gas mixture immediately1 after it leaves the heating device and ,previous to its entrance in the cooling path is brought down every time to a temperature below that at which any considerable percentage of the reaction products and start-ing materials would dissociate 0r decompose, continuously 4.removing by means of a lateral circuit a part of the mass in circulation and introducing a corresponding quantity of fresh gases into the circulation.

2. In a process for carrying out endothermic gas reactions wherein the gases are maintained in continual circulation through a `heating device and a subsequent cooling path, the steps which consist in circulating the gases at a speed so high that under the influence of the excess of non-combined gases the gas mixture immediately after it leaves the heatin device and revious to its entrance in Ile cooling pat lis brought down every time to a tem erature below that at which any considera le percentage of the reaction products and starting materials would dissociate or decompose, continuously removing by means of a lateral circuit a vpart of the mass in circulation, which is freed from reaction .products and thereafter reintroduced in the principal circuit and, in order to replace the gases bound in the eliminated reaction products, introducing a correspondingquantity of fresh gases into the said principal circuit.

3. ln a process for carrying out endothermic gas reactions whereln the gases are maintained in continual circulation through a heatingl device and a subsequent cooling path, the steps which consist in circulating the gases at a 'speed so high that under the influence of the excess of non-combined gases the gas mixture immediately after it leaves the heating device and previous to its entrance in the cooling path is brought down every time to a temperature :below that at which any considerable percentage of the reaction' products and starting materials woulddi'ssociate or decompose, continuously removing by means of a lateral circuit a part of the mass in circulation,-

which is freed from reaction products and thereafter reintroduced in the principal circuit and, in order to replace the gases` bound in the eliminated reaction products, introducing a` corresponding quantity of fresh gases into the said principal circuit through the lateral circuit.

4. In a process for carrying out endothermic gas reactions wherein the gases are maintained in continual circulation through a heating device and a subsequent cooling path, the steps which consist in circulating the gases at a speed so high that under the infiucnce `of 'the excess ofnon-combined gases the gas mixture immediately after it leaves theheating device and previous to its entrance in the cooling path is brought down every time to a temperature below that at which any considerable percentage of the reaction products and starting materials would dissociate or decompose, continuously' removing by means of a later-al circuit a part of the mass in circulation, which is freed from reaction products and thereafter reintroduced in the principal cir-` F. HEIM, D. GRAF.

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